Blast actuated ventilator valve



Nov. 19, 1963 R. A. BRECKENRIDGE 3,111,078

BLAST ACTUATED VENTILATOR VALVE Filed Dec. 14, 1961 E G Y. H m E RR N mmR 4 NK 0 .3 mm w NR 1 w 57 2 R W 9 0 2 G 6 w n a s ;& 6 2 M 4M24 UnitedStates Patent O 3,111,078 BLAST ACTUATED VENTILATGR VALVE Robert A.Breckenridge, 437 N. M t., Oxnard, Calif. Filed Dec. 14, 1361, Ser. No.159,469 1 Claim. (Cl. 98-419) (Granted under Title 35, US. Code (1952),sec. 266) The invention described herein may be manufactured and used byor for the Government of the United States of America for governmentalpurposes without the payment of any royalties thereon or therefor.

This invention relates generally to the ventilation of undergroundpersonnel shelters for use in the vicinity of possible nuclear bombattacks and specifically to a ventilating closure which may be actuatedby the bomb blast itself.

One of the most important considerations in the de sign of undergroundshelters for use in the protection of personnel from nuclear attacks isadequate ventilation. Normall, such ventilation may be provided by oneor more ventilation pipes or ducts leading from the shelter to thesurface of the ground above. In the event of the explosion of an atomicbomb or other nuclear device within effective range of the shelters,some provision must be made to immediately seal-off the ventilation ductleading to such shelter. Conversely, when the worst effects of the bombhave passed on over, the sealing-off or closure device shouldautomatically open the ventilation duct for its intended purpose.

Other types of blast valves have been previously developed for suchpurposes. Such valves, however, have usually been connected with theupper exposed end of the ventilation duct and have thus been subject toinitial blast damage. Also, such blast valves have generally beensecondarily actuated by mechanical or electrical means triggered by aprimary means operable as a function of the pressure of the blast waveor as a function of the intense light produced by the initial explosion.Such methods have been found too complex with decreased reliability inproportion to increased complexity. Furthermore, such prior valves havebeen one-shot devices. After each blast, they required re-cocking,recharging (in the case of valves operated by small explosive charges),re-opening, or otherwise the attention of trained personnel with theadditional hazard of the exposing of such personnel to radioactivefallout.

The principal object of my invention, therefore, is to provide a blastactuated ventilator valve that is simply constructed and positivelyoperated by the blast wave from the explosion of a nuclear device.

Another object of my invention is to provide a blast actuated closurefor a ventilator duct which is continu ously repeatable in actionwithout the necessity of recharging or recocking or other mechanical orelectrical manipulation after each blast.

A further object of my invention is to provide a blast actuatedventilator valve which establishes a positive seal in a ventilation ductfor protective shelters and is capable of continuous, automatic actionin preventing the ingress of blast waves regardless of duration andfrequency.

Other objects and advantages of this invention will be appreciated inconjunction with the following detailed description and accompanyingdrawings wherein:

FIGURE 1 is a partially cross-sectional elevation of an undergroundshelter showing the ventilation duct attached to one end thereof;

FIG. 2 is a partial sectional side elevation of the blast closurestructure;

FIG. 3 is a cross-sectional front elevation of the blast closurestructure taken on the line 33 of FIG. 2; and

3,1 1 1,078 Patented Nov. 19, 1963 FIG. 4 is a partial cross-sectionalview showing one mode of operation of my invention.

With reference to FIG. 1 showing the general arrangement, theunderground shelter 10 may be constructed of reinforced concrete with anhemispherical roof 11 and end walls 12. A heavy door 13 is provided inone of the end walls which opens from the shelter into a protectedhorizontal passage 14 which, in turn, communicates with a ladderedvertical shaft 15. This latter shaft or passage may be covered with aheavy cover 16 which may be hinged or otherwise arranged for beingsecured in place by the last person descending shaft 15.

A ventilating duct 17 communicates with the interior of the shelterthrough the other end wall 12 and is extended upwardly until it risesjust below the surface 18 of the ground over the shelter. A heavierfitting 19 may be fitted over the upper end of the ventilation duct forits protection. This fitting 19 may be flush with the surface 18 orextend slightly above it as shown. This fitting may also be providedwith some form of cover or other closure for sealing the upper end ofthe ventilation duct when the shelter is not in use.

The ventilation duct 17 comprises an upper pipe or conduit 20, a valvecasing 22 and a U-shaped conduit 24.

As shown in FIGS. 2, 3, and 4, pipe or conduit 20 and U-shaped conduit24 consist of sheet metal pipe having a circular cross-section. Theseconduits, however, may be of any suitable similar configuration and maybe composed of any suitable material other than sheet metal.

Valve casing 22 is generally rectangular in cross section and has a top25, side walls 26 and 27, end walls 28 and 29, and a bottom 30. Casing22 is provided with a central dividing wall 31 which is parallel to theend walls 23 and 29 and thus divides the interior of the casing into twopassages or chambers 32 and 33. This dividing wall 31 extends from topto bottom, side wall to side wall and may be soldered, brazed orotherwise sealingly secured in place in the interior of the casing 22.

The top cover 25 of the casing 22 is provided with an orifice 34communicating with the blast chamber or passage 32. The lower end ofconduit 20 may be fitted into this orifice and sealingly secured thereinor, for ease of construction and assembly, a fitting 35 may be securedin the orifice 34 which fitting will be adapted to receive the lower endof the conduit 20. A similar grifice 36 is provided in end wall 29 foran horizontal conduit or conduit fitting 37 which may lead into theinterior of shelter it through end wall 12 and which communicates withthe shelter chamber 33.

The bottom 30 is provided with two orifices 38 and 39 into which theends of the U-shaped conduit 24 may be sealingly inserted or, again,fittings 40 and 41 may be secured to the bottom of the casing whichfittings are adapted to receive and securely hold the upper ends of theU-shaped conduit 24. It will be noted that this U- shaped conduit thusprovides an 180 curved passageway connecting the two chambers 32 and 33.

Dividing wall 31 is provided with an horizontal aperture 42 which isadapted to receive the central portion of the dihedral moving valvemember 43. This latter part is supported by a shaft 44 which protrudesthrough and is journalled by the side walls 26 and 27, as shown at 45 inFIG. 2.

Moving valve member 43 is made from two plane surface vanes 46 and 47which are connected to a central shaft receiving portion 4% at an anglepreferably not less than 99". This included angle is not critical otherthan it should for complete ope-ration be not less than With the vanes46 and 47 being of equal surface and weight, the valve member 43, underthe influence of gravity, will assume the normal position shown in FIG.3. Extending horizontally inwards. from the end walls and generally inline with the dividing wall aperture 42, sealin-g lips 49 are shown inFIGS. 3 and 4. These sealing lips are adapted to cooperate with thevanes of the dihedral moving valve member so as to prevent or inhibitany unusual flow of air through the ventilating system. While shown asextending laterally only from the end walls 28 and 2 9, similar lipscould be installed in coplanar relationship with the first set of lipson the inner portions of side walls 26 and 27. Also, with only the twolips as shown, sealing material could be supplied to the verticalinclined edges ofthe vanes 46- and 47 so that a seal could be providedbetween the ends of the moving valve member and the side walls of thecasing.

In the operation of my improved blast actuated ventilator valve, thenormal flow of air is indicated by the anrows 50 where the closed endindicates ingress air flowing into the shelter and the open endindicating egress air flowing out of the shelter to atmosphere. Thusunder normal conditions, valve member 43 is in the neutral position asshown in FIG. 3 and air may circulate to and from the interior of theshelter to atmosphere. It should be noted here that while only oneventilating duct system is shown, other similar systems could beinstalled on the same shelter for more natural circulation of airthrough the shelter. Fans or blowers could be easily installed in one ormore of such ventilating duct systems to promote a forced circulationthrough the shelter. In this ciroumstance, under normal conditions, onesystem. would be used for supplying air to the shelter and the othersystems could be used for exhaust.

With the occurrence of the atomic or nuclear blast, the pressure wavewould enter the duct 20 and proceed downwardly therethrough. As thefront of the pressure wave reaches the vane 46 it moves the latterdownwardly and commences to close off the passage of the pressure wavethrough the shelter chamber 33. As the pressure wave continues itstortuous passage through the U-shaped conduit 24, it then enters shelterchamber 33 and impinges against the lower surface of vane '47. Thisimpingement forces vane 47 against the lower surface of sealing lip 49which effectually seals off this passage or chamber 33 and prevents orgreatly inhibits the passage of the pressure wave into the shelter. Thislatter condition is shown in FIG. 4. As the pressure wave diminishes,valve member '43 tends to return to its normal position which it assumeswhen the pressure of the air in the shelter equals that of theatmosphere above ground surface 18.

In the event a negative pressure condition in the atmosphere follows thepressure phenomenon, the moving valve member will then be moved in theopposite direction to seal chamber 32 and prevent or inhibit the escapeof air from the shelter. It should be noted here that one of theprincipal features of my invention resides in my having provided a blastactuated closure valve in which the blast or pressure wave must travel acomparatively considerable distance after initiating the actuation ofthe valve and before reaching the closing off or sealing portion. Duringthis travel, the pressure wave is subject to a definite and measurableattentuation in force. Thus, if the initial pressure wave is ofsuffioient magnitude, its impingement against the upper surface of thevane 46 in the blast chamber 32 will be suificient to force vane 47upwardly in sealing position before the wave front enters the shelterchamber .33. This action insures that the valving or sealing portion ofthe valve will be substantially closed before the blast impulse reachesit.

While a preferred embodiment of the invention has thus been describedand shown, I do not intend to be limited thereby. Obviously manymodifications and variations of the present invention are possible inthe light of the above teachings. One modification, for instance, couldbe performed by slightly elongating, in a vertical direction, thebearing holes for the valve member shaft 44 which bearing holes areformed in the side walls 26 and 27 of casing 22. This elongation wouldpermit a possibly improved sealing action of the valve vane 47 againstthe sealing lips, particularly where such sealing lips are provided onthe side walls as mentioned above. It is to be further understood,therefore, that within the scope of the appended claims the inventionmay be practiced otherwise than as specifically described.

Having thus described my invention, 1 claim:

In a ventilation system for underground shelters adapted to protectpersonnel from the positive and negative air pressure phases of theblast from high order explosive comprising, in combination:

a dual chambered casing installed in the ground adjacent one end of saidunderground shelter, said casing having a vertical median wall dividingsaid casing into two vertical chambers and said vertical median wallhaving a centrally disposed horizontal aperture formed therein;

a substantially vertical ventilation duet leading from the surface ofthe ground above said shelter to said casing, said vertical duct beingconnected to the upper portion of one of said vertical chambers in saidcasing;

a substantially horizontal ventilation duct leading from the upperportion of the other of said vertical chambers to the interior of saidshelter;

a U-shaped conduit depending from the lower portion of said casing, saidU-shaped conduit providing a passage from said one of said verticalchambers to to the other of said vertical chambers;

horizontally disposed sealing lips supported internally of the walls ofsaid casing, said sealing lips being substantially coplanar with thehorizontal aperture in said vertical median wall; and

a movable dihedral valve means having two planar vanes extending throughsaid horizontal aperture in said vertical media-n wall, the apex of saidvalve memher being rotatably supported in said aperture, one of thevanes of said dihedral member extending into one of the said verticalchambers and the other vane extending into the other of said verticalchambers, the dihedral angle of said valve means being not less thanninety degrees, and the said vanes of said dihedral valve means beingadapted to contact the under surfaces of said sealing lips and close thepassage defined by said chambers and said U-shaped conduit when a blastof pressurized air impinges first on the upper surface of one of saidvanes and then secondly on the lower surface of the other vane aftersaid blast of pressurized air has passed through said U-shaped conduit.

References Cited in the file of this patent UNITED STATES PATENTSSchuster June 17, 1958 Drayer Feb. 17, 1959 FOREIGN PATENTS

